Fumigation trials with farm-stored grain.
Fumigation (against Sitophilus oryzae, Rhyzopertha dominica, Tribolium castaneum, Latheticus oryzae and Cryptolestes sp.) of grain stored in bolted-iron farm silos was investigated at 3 places in New South Wales in 1976-82. Fumigant leakage from unsealed bins reduced the effectiveness of carbon disulfide applied at dosages that were effective for 24-h fumigation in bins enveloped in plastic sheeting. Fumigation with 2, 6 or 12 g phosphine/t, applied as tablets containing aluminium phosphide probed into the grain, was effective both in unsealed bins and in bins enveloped in plastic sheeting for 7-10 days. Another tablet formulation containing aluminium phosphide, urea and ammonium bicarbonate, tested in conjunction with the aluminium phosphide-ammonium carbamate formulations used previously in these trials, gave similar results at 6 g phosphine/t after 7-8 days in unsealed bins.